In a wireless network system, before occupying an unlicensed carrier channel to send a signal, a transmission node in a network needs to listen to the channel, and after detecting that the channel is idle, the transmission node occupies the channel to send the signal. For example, in an LAA-LTE (Licensed Assisted Access Using Long Term Evolution) system, when using channel resources in an LBT (Listen Before Talk) manner, a device needs to first listen to a channel. A process of determining whether the channel is idle is referred to as a CCA (Channel clearance Assessment), and a minimal time unit of a channel assessment is referred to as a CCA cycle.
In the LAA-LTE system, before sending data, the device needs to detect, by means of listening by repeatedly using the CCA, that a channel is idle, so that the device can start to send the data. If multiple devices simultaneously detect, by means of listening, the channel is idle and simultaneously send data, a channel occupancy collision is caused.